Diagnostic Immunology Flashcards
In regards to agglunation reactions, both antigen and antibody must be at least bivalent. Why?
Fab won’t work if they aren’t
People with infectious mononucleosis caused by Epstein Barr Virus produce ____ antibodies during infection. These antibodies will cross-link antigens on the surface of red blood cells of certain animal species.
heterophile (“different loving”)
A positive heterophile antibody test is confirmatory for what?
infectious mononucleosis caused by EBV
For the following situations, give the blood type - If your red blood cells stick together when mixed with: Anti-A Anti-B Neither anti-A or anti-B Anti-A and anti-Rh Anti-B but not anti-Rh Anti-A, anti-B, and anti-Rh Anti-Rh, but neither anti-A or anti-B
Anti-A: type A Anti-B: type B Neither anti-A or anti-B: type O Anti-A and anti-Rh: type A+ Anti-B but not anti-Rh: type B- Anti-A, anti-B, and anti-Rh: AB+ Anti-Rh, but neither anti-A or anti-B: type O+
What does the direct coombs test detect?
detects antibodies already bound to the surface of erythrocytes
This test is often used to test the red blood cells of a newborn suspected of having hemolytic disease of the newborn for the presence of maternal IgG antibodies bound to the Rh antigen
Direct coombs test
What does the indirect coombs test detect?
detects circulating IgG that are specific for surface antigens on red blood cells
This test is often used to detect anti-Rh IgG antibodies in the circulation of Rh- women who have given birth to Rh+ children
indirect coombs test
The indirect coombs test is subject to misinterpretation due to the prozone effect. Explain
in the prozone, antibody concentration is high relative to antigen concentration, resulting in very small complexes that do not clump to form visible agglutination. As the serum is diluted further, agglutination becomes visible throughout the equivalence zone and becomes negative again after the serum is diluted beyond its maximum titer
Precipitation reactions work much like agglutination reactions except that the antigen being cross-linked is a ___ substance rather than a ____ particle
soluble; insoluble
The following describes what test?: When soluble antigens and antibodies are placed in wells cut in an agar gel, the reactants diffuse in the gel and form gradients of concentration, with the highest concentrations closest to the well. Somewhere between the two wells, the reacting antigen and antibodies will be present at optimal proportions for formation of a visible precipitate.
ouchterlony test or immune-double diffsusion technique
The following describes what test?: an in-gel precipitation reaction often used to quantitate human Ig isotopes in serum. Antibody is mixed homogeneously throughout the agarose gel. Wells are cut in the agarose and filled with various amounts of antigen. Upon diffusion of the reactants, precipitin rings form. The diameter of the precipitin ring is directly proportional to the concentration of the antigen in the well. From the results obtained with known standard concentrations, a calibration curve is constructed, permitting quantitation of the antigen whose concentration was previously unknown
Radial immunodiffusion test (RID)
In immunoelectrophoresis, antigens are separated in an agar gel by applying an electrical charge. The pH of the buffer in the gel is chosen so that positively charged proteins move toward the cathode and negatively charged proteins move toward the anode. A trough is then cut between the wells and filled with antibody, which is allowed to diffuse. The antigens and antibodies form ____ ___ where they meet at equivalence. This method is often used to characterize ___ ____ proteins
precipitin arcs; human serum
